The invention relates to an electronic circuit in a package-in-package (PiP) configuration and to a production method for such a circuit.
Electronic circuits in a package-in-package configuration, referred to hereinafter as PiP configuration, include an encapsulated active electronic component, in particular a semiconductor element or a semiconductor chip with an integrated circuit, which is mechanically fixed and electrically contact-connected on an element carrier generally together with further electronic components. An inner contact-connection is led from the element carrier to a leadframe. The encapsulated active component, the element carrier, the inner contact-connection and the leadframe are in turn enclosed with one another into a housing, for example by using a molding compound.
The electronic linking of this encapsulated arrangement toward the outside is formed by an inner lead which leads from the encapsulated leadframe toward the outside, runs within the encapsulation and joins an outer contact-connection. The PiP configuration mentioned is finally anchored on a larger printed circuit board of a corresponding final product.
PiP configurations of this type are produced by applying a housed electronic component, where necessary also together with other components, to the internal element carrier and anchoring the component(s) there. The element carrier is then contact-connected, in particular bonded, to the leadframe. Afterward, the leadframe together with the element carrier and the electronic components situated thereon is encapsulated with the exception of the outer contact-connections, by molding compound being molded on.
FIG. 1 illustrates an embodiment of a PiP configuration in a view from above. An active electronic component, in particular a semiconductor device 20, and a further component 30 are situated within an outer encapsulation 10, which is usually composed of a molding compound. In this case, the semiconductor element 20 is accommodated in a first encapsulation, which is not explicitly illustrated here, and is contact-connected onto an element carrier 40.
The element carrier is generally formed as an internal printed circuit card. The element carrier is surrounded by a leadframe 50 and electrically contact-connected thereto via inner contact-connections 51. That part of the leadframe which runs within the encapsulation forms an inner lead 60. The terminal parts of the leadframe which are led out from the encapsulation form a series of outer contact-connections 70 of the component, the conventional “pins”, in the PiP configuration.
In this case, a sealing web 75 or a comparable means can be provided in the region of the outer contact-connections 70. It encloses the interfaces between the encapsulation 10 and the outer contact-connections 70 and tightly connects the outer contact-connections to the encapsulation. In the case of the example illustrated in FIG. 1, the inner passive electronic component 30 is contact-connected on the inner lead 60 and likewise encapsulated.
In the case of the example of FIG. 1, the semiconductor element 20, the passive component 30, the element carrier 40, the leadframe 50, the contact-connections 55 and the inner lead 60 are all concealed under the encapsulation 10. The only possibility for contact-connection of the PiP configuration is via the outer contact-connections 70, which are usually anchored on an outer printed circuit board or circuit board (likewise not illustrated here). In a corresponding manner, all required additional electronic components or circuits that are to be provided in supplementation to the PiP configuration are arranged on the outer printed circuit board and demand a corresponding space and a specific individual design of the printed circuit board. The design of the printed circuit board has to be planned anew in each case depending on the circuit to be realized.
Additional electronic individual components, in particular resistors, transistors, diodes or capacitors, have hitherto been arranged individually on a printed circuit board alongside the PiP configuration. This takes place even when they are in a direct circuitry relationship with the PiP configuration. The space taken up by the PiP configuration and the components on the printed circuit board is correspondingly large in this case. Since the (passive) individual components are anchored fixedly and separately on the printed circuit board, a prior functional test of the interaction of the components with the PiP configuration and an exchange that may be required are not possible, or are possible only with a very high outlay.
Depending on the required task of the PiP configuration, a given PiP configuration often has to be combined with different passive components. However, the rigid and separate arrangement of the passive components on the printed circuit board prevents a genuinely modular use of the PiP configuration and requires a complicated redesign of each printed circuit board on account of the different passive components in each case.
Recourse is also had variously to solutions using multichip modules. Embodiments of this type are expensive and have a series of disadvantages, in particular a loss of yield, i.e. a decrease in productivity, material and effectiveness, in the case of a negative functional test due to a loss of good electronic components.
For these and other reasons, there is a need for the present invention.